The main goal of a research project on wind barriers was to get more information about the influence of wind pressure on the heat loss from wood frame constructions. The project was divided into three parts: calculations, hot-box measurements and wind pressure measurements on a rotatable test house, The theoretical studies as well as the experimental investigations in the hot-box, have been restricted to one specific type of forced convection in the thermal insulation, called "anblasning", i.e.
The actual heating load of a building differs often from the designed load. One reason for this is the uncontrolled ventilation through a building envelope. The heating load of air infiltration has, in practical calculations, been calculated according to the predicted leakage flow rate and to the indoor and outdoor air temperature difference. We suggest, however, that the value of transmission heat losses should be corrected by a factor, Nusselt number, because of the thermal interaction of leakage flows and conduction heat transfer in wall structures.
This paper describes one of the results of the IEA-annex 8 "Inhabitants behaviour with regard to ventilation". Annex 8 has shown that the occupants can play a rather important role with regard to the ventilation rates inoccupied buildings. This paper gives some practical 'rules of thumb' for estimating air flow rates through open windows. An overview of measured and estimated ventilation rates in houses is given from which a simplified approach is derived that takes into account the air tightness of the building and the behaviour.
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